Ultrasound diagnostic apparatus, method for controlling ultrasound diagnostic apparatus, and readable recording medium recording a program for controlling ultrasound diagnostic apparatus

ABSTRACT

An ultrasound diagnostic apparatus 1 includes an image acquisition unit  3  that generates an ultrasound image, an image recognition unit  9  that performs image recognition for the ultrasound image to calculate recognition scores, an index value calculation unit  10  that calculates index values of a plurality of parts on the basis of the recognition scores calculated for a predetermined number of ultrasound images, a part narrowing-down unit  11  that narrows down target parts for which part determination is to be performed, from the plurality of parts on the basis of the index values, and a part determination unit  12  that determines an imaging part of the subject on the basis of the recognition scores calculated by the image recognition unit  9  for the target parts narrowed down by the part narrowing-down unit  11.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2018/001347 filed on Jan. 18, 2018, which claims priority under 35U.S.C. § 119(a) to Japanese Patent Application No. 2017-016578 filed onFeb. 1, 2017. The above application is hereby expressly incorporated byreference, in its entirety, into the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an ultrasound diagnostic apparatus, amethod for controlling an ultrasound diagnostic apparatus, and areadable recording medium recording a program for controlling anultrasound diagnostic apparatus, and more particularly, to an ultrasounddiagnostic apparatus that determines an imaging part of a subject, amethod for controlling the ultrasound diagnostic apparatus, and areadable recording medium recording a program for controlling theultrasound diagnostic apparatus.

2. Description of the Related Art

In recent years, an ultrasound diagnostic apparatus has been known as anapparatus for obtaining an image of the inside of a subject. In general,the ultrasound diagnostic apparatus comprises an ultrasound probecomprising a transducer array in which a plurality of elements arearranged. In a state in which the ultrasound probe is in contact withthe body surface of the subject, ultrasound beams are transmitted fromthe transducer array to the subject and the transducer array receivesultrasound echoes from the subject. In this way, element data isacquired. In addition, the ultrasound diagnostic apparatus electricallyprocesses the obtained element data to generate an ultrasound image of acorresponding part of the subject.

It has been known that, in a case in which the ultrasound image of apart of the subject is generated by the ultrasound diagnostic apparatus,there are imaging conditions suitable for each part. It is preferablethat the imaging conditions are automatically set in a case in which theultrasound image of each part is generated. However, it is necessary toautomatically determine an imaging part of the subject which iscurrently being examined in order to automatically set the imagingconditions.

Therefore, various proposals have been made as the ultrasound diagnosticapparatus that can automatically determine an imaging part of a subject.For example, an ultrasound diagnostic apparatus disclosed inJP1992-224738A (JP-H04-224738A) includes a pattern memory that storescharacteristic patterns of each part of a subject, collates an imagepattern extracted from a generated ultrasound image with a plurality ofpattern data items stored in the pattern memory, detects pattern datasimilar to the image pattern included in the generated ultrasound image,and determines an imaging part.

SUMMARY OF THE INVENTION

However, in general, the amount of calculation load required for imagerecognition that extracts an image pattern from a generated ultrasoundimage and collates the extracted image pattern with pattern data storedin advance is large. In particular, in a case in which the imagerecognition is performed by an apparatus with a low processingperformance, it takes a lot of time until the image recognition iscompleted. In addition, in the ultrasound diagnostic apparatus disclosedin JP1992-224738A (JP-H04-224738A), in a case in which the imagerecognition is performed for a plurality of parts of the subject, it isnecessary to collate the image pattern extracted from the generatedultrasound image with many pattern data items corresponding to theplurality of parts. As a result, the time required to determine theimaging part further increases. In addition, in the ultrasounddiagnostic apparatus disclosed in JP1992-224738A (JP-H04-224738A), thisprocess needs to be performed for each of the plurality of parts of thesubject.

The invention has been made in order to solve the problems of therelated art and an object of the invention is to provide an ultrasounddiagnostic apparatus that can reduce the time required to determine animaging part, a method for controlling the ultrasound diagnosticapparatus, and a readable recording medium recording a program forcontrolling the ultrasound diagnostic apparatus.

In order to achieve the object, an ultrasound diagnostic apparatusaccording to the invention comprises: an image acquisition unit thattransmits an ultrasound beam from an ultrasound probe to a subject togenerate an ultrasound image; an image recognition unit that performsimage recognition for the ultrasound image generated by an imageacquisition unit to calculate recognition scores of a plurality of partsof the subject; an index value calculation unit that calculates indexvalues of the plurality of parts on the basis of the recognition scoresof the plurality of parts calculated for a predetermined number ofultrasound images; a part narrowing-down unit that narrows down targetparts for which part determination is to be performed, from theplurality of parts on the basis of the index values; and a partdetermination unit that determines an imaging part of the subject on thebasis of the recognition scores calculated by the image recognition unitfor the target parts narrowed down by the part narrowing-down unit.

Preferably, the index value calculation unit uses, as the index valuesof the plurality of parts, recognition scores of the plurality of partscalculated by the image recognition unit for a latest ultrasound imageacquired by the image acquisition unit.

The index value calculation unit may calculate the index values of theplurality of parts using recognition scores of the plurality of partscalculated by the image recognition unit for each of a plurality ofultrasound images which are continuously acquired in time series andinclude a latest ultrasound image acquired by the image acquisitionunit.

Preferably, the index value calculation unit uses mean values or mediansof the recognition scores of the plurality of parts calculated for theplurality of ultrasound images, as the index values of the plurality ofparts.

The index value calculation unit may use maximum values or minimumvalues of the recognition scores of the plurality of parts calculatedfor the plurality of ultrasound images, as the index values of theplurality of parts.

The index value calculation unit may calculate weighted mean values ofthe recognition scores of the plurality of parts by giving a largerweight to an ultrasound image more recently acquired by the imageacquisition unit among the plurality of ultrasound images, and may usethe weighted mean values as the index values of the plurality of parts.

The index value calculation unit may give ranking scores to theplurality of parts for each of the plurality of ultrasound images suchthat the part with a higher recognition score has a higher rankingscore, and may use sums of the ranking scores of the plurality of partsfor the plurality of ultrasound images, as the index values of theplurality of parts.

The index value calculation unit may have a threshold value of therecognition score, and may use the number of recognition scores greaterthan the threshold value among the recognition scores of the pluralityof parts calculated for the plurality of ultrasound images, as the indexvalue of each of the plurality of parts.

Preferably, the ultrasound diagnostic apparatus further comprises aprobe state detection unit that detects a change in an imaging partcaused by movement of the ultrasound probe. Preferably, the index valuecalculation unit starts to calculate the index value after the probestate detection unit detects the change in the imaging part.

Preferably, the part narrowing-down unit has a narrowing-down thresholdvalue for the index value, and narrows down the plurality of parts ofthe subject having the index value greater than the narrowing-downthreshold value, as the target parts.

Preferably, the ultrasound diagnostic apparatus further comprises anorder decision unit that decides a determination order in which partdetermination is performed for the plurality of parts, on the basis ofthe index values. Preferably, the order decision unit decides thedetermination order such that the part with a larger index value isranked higher.

Preferably, in a case in which the imaging part is not decided for allof the target parts narrowed down by the part narrowing-down unit, thepart determination unit determines the imaging part for the parts otherthan the target parts among the plurality of parts.

According to the invention, there is provided a method for controllingan ultrasound diagnostic apparatus. The method comprises: transmittingan ultrasound beam from an ultrasound probe to a subject to generate anultrasound image; performing image recognition for the ultrasound imageto calculate recognition scores of a plurality of parts of the subject;calculating index values of the plurality of parts on the basis of therecognition scores of the plurality of parts calculated for apredetermined number of ultrasound images; narrowing down target partsfor which part determination is to be performed, from the plurality ofparts on the basis of the index values; and determining an imaging partof the subject on the basis of the calculated recognition scores for thenarrowed-down target parts.

According to the invention, there is provided a readable recordingmedium recording a program for controlling an ultrasound diagnosticapparatus. The program comprises: a step of transmitting an ultrasoundbeam from an ultrasound probe to a subject to generate an ultrasoundimage; a step of performing image recognition for the ultrasound imageto calculate recognition scores of a plurality of parts of the subject;a step of calculating index values of the plurality of parts on thebasis of the recognition scores of the plurality of parts calculated fora predetermined number of ultrasound images; a step of narrowing downtarget parts for which part determination is to be performed, from theplurality of parts on the basis of the index values; and a step ofdetermining an imaging part of the subject on the basis of thecalculated recognition scores for the narrowed-down target parts.

According to the invention, the ultrasound diagnostic apparatus includesthe part narrowing-down unit that narrows down the target parts forwhich the part determination is to be performed, and determines theimaging part of the subject for the narrowed-down target parts.Therefore, it is possible to reduce the time required to determine theimaging part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the configuration of anultrasound diagnostic apparatus according to Embodiment 1 of theinvention.

FIG. 2 is a block diagram illustrating the internal configuration of areceiving unit illustrated in FIG. 1.

FIG. 3 is a block diagram illustrating the internal configuration of animage generation unit illustrated in FIG. 1.

FIG. 4 is a flowchart illustrating an operation of the ultrasounddiagnostic apparatus according to Embodiment 1 of the invention.

FIG. 5 is a flowchart illustrating a part determination operation of theultrasound diagnostic apparatus according to Embodiment 1 of theinvention.

FIG. 6 is a flowchart illustrating an operation of an ultrasounddiagnostic apparatus according to Embodiment 2 of the invention.

FIG. 7 is a flowchart illustrating a part determination operation of anultrasound diagnostic apparatus according to Embodiment 3 of theinvention.

FIG. 8 is a flowchart illustrating a determination operation for partswhich are not narrowed down in Embodiment 3.

FIG. 9 is a flowchart illustrating a part determination operation of anultrasound diagnostic apparatus according to Embodiment 4 of theinvention.

FIG. 10 is a block diagram illustrating the configuration of anultrasound diagnostic apparatus according to Embodiment 5 of theinvention.

FIG. 11 is a flowchart illustrating a part determination operation ofthe ultrasound diagnostic apparatus according to Embodiment 5 of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the invention will be described withreference to the accompanying drawings.

Embodiment 1

FIG. 1 illustrates the configuration of an ultrasound diagnosticapparatus according to Embodiment 1 of the invention. An ultrasounddiagnostic apparatus 1 comprises an ultrasound probe 2 provided with atransducer array 2A. A display control unit 7 and a display unit 8 aresequentially connected to the ultrasound probe 2 through an imageacquisition unit 3.

The image acquisition unit 3 includes a receiving unit 4 and atransmitting unit 5 that are connected to the transducer array 2A of theultrasound probe 2, and an image generation unit 6 that is connected tothe receiving unit 4. The display control unit 7 is connected to theimage generation unit 6. In addition, an image recognition unit 9 isconnected to the image generation unit 6. An index value calculationunit 10 is connected to the image recognition unit 9. A partnarrowing-down unit 11 is connected to the index value calculation unit10. A part determination unit 12 is connected to the part narrowing-downunit 11. Further, the image recognition unit 9 is connected to the partdetermination unit 12. Furthermore, a probe state detection unit 13 isconnected to the image generation unit 6.

In addition, an apparatus control unit 14 is connected to the imageacquisition unit 3, the display control unit 7, the image recognitionunit 9, the index value calculation unit 10, the part narrowing-downunit 11, the part determination unit 12, and the probe state detectionunit 13. An operation unit 15 and a storage unit 16 are connected to theapparatus control unit 14. The apparatus control unit 14 and the storageunit 16 are connected such that information can be bi-directionallytransmitted and received therebetween.

The transducer array 2A of the ultrasound probe 2 illustrated in FIG. 1includes a plurality of elements (ultrasound transducers) which areone-dimensionally or two-dimensionally arranged. Each of the elementstransmits ultrasonic waves in response to a driving signal supplied fromthe transmitting unit 5. In addition, each of the elements receivesultrasound echoes from a subject and outputs a received signal. Each ofthe elements is, for example, a transducer in which electrodes areformed at both ends of a piezoelectric body made of piezoelectricceramic typified by lead zirconate titanate (PZT), a polymerpiezoelectric element typified by polyvinylidene difluoride (PVDF), or apiezoelectric single crystal typified by lead magnesium niobate-leadtitanate (PMN-PT).

In a case in which a pulsed voltage or a continuous-wave voltage isapplied to the electrodes of the transducer, the piezoelectric body isexpanded and contracted and pulsed or continuous ultrasonic waves aregenerated from each transducer. The ultrasonic waves are combined toform an ultrasound beam. In addition, each transducer receivespropagated ultrasonic waves, is expanded and contracted, and generatesan electric signal. The electric signal is output as a receivedultrasound signal from each transducer to the receiving unit 4.

As illustrated in FIG. 2, the receiving unit 4 of the image acquisitionunit 3 has a configuration in which an amplification unit 17 and ananalog/digital (A/D) conversion unit 18 are connected in series to eachother. The receiving unit 4 outputs, to the image generation unit 6,element data obtained by amplifying the received signal output from eachelement of the transducer array 2A with the amplification unit 17 andconverting the amplified signal into a digital signal with the AIDconversion unit 18.

The transmitting unit 5 of the image acquisition unit 3 includes, forexample, a plurality of pulse generators, adjusts the amount of delay ofeach driving signal such that the ultrasonic waves transmitted from theplurality of elements of the transducer array 2A form an ultrasoundbeam, on the basis of a transmission delay pattern selected according toa control signal from the apparatus control unit 14, and supplies thedriving signals to the plurality of elements.

As illustrated in FIG. 3, the image generation unit 6 of the imageacquisition unit 3 has a configuration in which a brightness-mode(B-mode) processing unit 19 and an image processing unit 20 aresequentially connected in series to each other.

The B-mode processing unit 19 performs a reception focusing processwhich applies a delay to each element data item following a set soundspeed on the basis of a reception delay pattern selected according to acontrol signal from the apparatus control unit 14 and adds the receiveddata (phasing addition). A sound ray signal in which the focus of theultrasound echo is narrowed is generated by the reception focusingprocess. In addition, the B-mode processing unit 19 corrects theattenuation of the sound ray signal caused by a propagation distanceaccording to the depth of the reflection position of ultrasonic wavesand then performs an envelope detection process to generate a B-modeimage signal which is tomographic image information related to thetissues in the subject. The B-mode image signal generated by the B-modeprocessing unit 19 is output to the image processing unit 20.

The image processing unit 20 converts the B-mode image signal generatedby the B-mode processing unit 19 into an image signal based on a generaltelevision signal scanning system (raster conversion), performs varioustypes of necessary image processing, such as a gradation process, forthe B-mode image signal, and outputs a B-mode image signal, that is, anultrasound image to the display control unit 7 and the image recognitionunit 9.

As illustrated in FIG. 1, the display control unit 7 of the ultrasounddiagnostic apparatus 1 directs the display unit 8 to display theultrasound image on the basis of the B-mode image signal acquired by theimage acquisition unit 3.

The display unit 8 includes a display device, such as a liquid crystaldisplay (LCD), and displays the ultrasound image under the control ofthe apparatus control unit 14.

The image recognition unit 9 receives the ultrasound image subjected tovarious types of image processing from the image processing unit 20 ofthe image generation unit 6 and performs image recognition, such aspattern recognition, for the ultrasound image to calculate recognitionscores of a plurality of parts of the subject. Here, the recognitionscores of the plurality of parts of the subject are the similarities ofimaging parts in the ultrasound image to the plurality of parts of thesubject. As the value of the similarity becomes larger, the probabilityof the imaging part in the ultrasound image being the corresponding partbecomes higher.

The index value calculation unit 10 calculates the index values of theplurality of parts of the subject on the basis of the recognition scoresof the plurality of parts of the subject calculated by the imagerecognition unit 9. There are various methods for calculating the indexvalues. Hereinafter, for the purpose of description, it is assumed thatthe index values of the plurality of parts of the subject are the meanvalues of the recognition scores of the plurality of parts of thesubject calculated for a plurality of ultrasound images. As such, in acase in which the index values are calculated on the basis of therecognition scores for a plurality of ultrasound images, the index valuecalculation unit 10 calculates the index values on the basis of therecognition scores for a plurality of ultrasound images which arecontinuously acquired in time series and include the latest ultrasoundimage acquired by the image acquisition unit 3.

The part narrowing-down unit 11 decides a part as a determination targetof the imaging part among the plurality of parts of the subject, on thebasis of the index values of the plurality of parts of the subjectcalculated by the index value calculation unit 10. At that time, thepart narrowing-down unit 11 narrows down the parts having index valuesgreater than a narrowing-down threshold value, as the determinationtarget of the imaging part. Here, the narrowing-down threshold value isa threshold value for the index value, which is set for narrowing downthe parts.

The part determination unit 12 determines the imaging part of thesubject for the ultrasound image acquired by the image acquisition unit3 on the basis of the recognition scores calculated by the imagerecognition unit 9. At that time, the part determination unit 12sequentially determines the imaging part from the part that is rankedfirst according to a predetermined order, for the parts narrowed down bythe part narrowing-down unit 11. Here, for the purpose of description,in Embodiment 1, it is assumed that a determination order of the partdetermination unit 12 for the plurality of parts of the subject isdetermined in advance by an input or the like by an operator through theoperation unit 15.

The probe state detection unit 13 determines whether the ultrasoundprobe 2 is in an aerial emission state. Here, the aerial emission stateof the ultrasound probe 2 means a state in which the ultrasound probe 2is separated from the body surface of the subject and the ultrasoundbeam transmitted from the transducer array 2A to the subject is emittedto the air. In a case in which the ultrasound probe 2 is in the aerialemission state, the ultrasound beam emitted from the transducer array 2Ais not reflected from a part of the subject and the received signalgenerated in the transducer array 2A does not have sufficient intensity.As a result, the image of the part is not included in the ultrasoundimage generated by the image generation unit 6. Therefore, the probestate detection unit 13 determines that the ultrasound probe 2 is in theaerial emission state in a case in which no image is included in theultrasound image and determines that the ultrasound probe 2 is incontact with the subject in a case in which an image is included in theultrasound image.

The apparatus control unit 14 controls each unit of the ultrasounddiagnostic apparatus 1 on the basis of commands input by an operatorthrough the operation unit 15.

The operation unit 15 is used by the operator to perform an inputoperation and may include, for example, a keyboard, a mouse, atrackball, and a touch panel.

The storage unit 16 stores, for example, an operation program of theultrasound diagnostic apparatus 1 and may be a recording medium, such asa hard disc drive (HDD), a solid state drive (SSD), a flexible disc(FD), a magneto-optical (MO) disc, a magnetic tape (MT), a random accessmemory (RAM), a compact disc (CD), a digital versatile disc (DVD), asecure digital (SD) card, or a universal serial bus (USB) memory, or aserver.

The image generation unit 6 of the image acquisition unit 3, the displaycontrol unit 7, the image recognition unit 9, the index valuecalculation unit 10, the part narrowing-down unit 11, the partdetermination unit 12, the probe state detection unit 13, and theapparatus control unit 14 are implemented by a central processing unit(CPU) and a control program that causes the CPU to perform variousprocesses. However, these units may be implemented by a digital circuitand a computer. In addition, some or all of the image generation unit 6,the display control unit 7, the image recognition unit 9, the indexvalue calculation unit 10, the part narrowing-down unit 11, the partdetermination unit 12, the probe state detection unit 13, and theapparatus control unit 14 may be integrated into one CPU.

Next, the operation of the ultrasound diagnostic apparatus 1 accordingto Embodiment 1 will be described with reference to a flowchartillustrated in FIG. 4.

First, in Step S1, the receiving unit 4 and the transmitting unit 5 ofthe image acquisition unit 3 perform the transmission and reception ofultrasound beams and scanning, that is, the capture of an ultrasoundimage, using the plurality of ultrasound transducers of the transducerarray 2A in the ultrasound probe 2. At that time, each ultrasoundtransducer which has received ultrasound echoes from the subjectgenerates a received signal and the received signal is input to thereceiving unit 4. The amplification unit 17 of the receiving unit 4amplifies the received signal input to the receiving unit 4. Inaddition, the A/D conversion unit 18 performs A/D conversion for thereceived signal. Furthermore, the received signal is input to the imagegeneration unit 6. The B-mode processing unit 19 of the image generationunit 6 generates a B-mode image, that is, an ultrasound image.

Then, in Step S2, the probe state detection unit 13 determines whetherthe ultrasound probe 2 is in the aerial emission state. In a case inwhich it is determined in Step S2 that the ultrasound probe 2 is in theaerial emission state, the process returns to Step S1. On the otherhand, in a case in which it is determined in Step S2 that the ultrasoundprobe 2 is not in the aerial emission state and is in contact with thebody surface of the subject, the process proceeds to Step S3.

In Step S3, the part determination is performed for the imaging partthat is currently being examined. The part determination in Step S3 willbe described in detail below with reference to FIG. 5.

In a case in which the imaging part is determined in Step S3, theprocess proceeds to Step S4. In Step S4, the apparatus control unit 14sets imaging conditions suitable for the part determined in Step S3.Here, the imaging conditions include, for example, a frame rate inultrasound diagnosis, the resolution of an ultrasound image, thebrightness of an ultrasound image, and a dynamic range in ultrasounddiagnosis.

Then, in Step S5, the image acquisition unit 3 acquires an ultrasoundimage. At that time, since the imaging conditions set in Step S4 areused as the imaging conditions, the image acquisition unit 3 can acquirethe ultrasound image in which the image of the imaging part is clear.

Then, in Step S6, it is determined again whether the ultrasound probe 2is in the aerial emission state. Here, in a case in which the probestate detection unit 13 determines that the ultrasound probe 2 is not inthe aerial emission state and is in contact with the body surface of thesubject, it is determined that the imaging part has not been changed andthe process returns to Step S5 to acquire an ultrasound image again. Onthe other hand, in a case in which the probe state detection unit 13determines that the ultrasound probe 2 is in the aerial emission state,it is determined that a change in the imaging part has started and theprocess returns to Step S1.

Next, the part determination in Step S3 will be described with referenceto FIG. 5. In a case in which the part determination in Step S3 starts,first, an ultrasound image is acquired in Step S7.

Then, in Step S8, the image recognition unit 9 calculates therecognition scores of a plurality of parts of the subject for theultrasound image acquired in Step S7.

Then, in Step S9, the apparatus control unit 14 determines whether therecognition scores of a plurality of parts of the subject have beencalculated for a predetermined number of frames of ultrasound images.Here, the part determination process in Step S3 has the determinationstep of Step S9 in order to obtain the number of recognition scoresrequired for the index value calculation unit 10 to calculate the indexvalues. Therefore, in a case in which it is determined in Step S9 thatthe recognition scores have not been calculated for a predeterminednumber of frames of ultrasound images, the process returns to Step S7 toacquire an ultrasound image. Then, in Step S8, a recognition score iscalculated for a new ultrasound image. As such, as a result of therepetition of Steps S7 and S8, in a case in which it is determined inStep S9 that the recognition scores of a plurality of parts of thesubject have been calculated for a predetermined number of frames ofultrasound images, the process proceeds to Step S10.

In Step S10, the index value calculation unit 10 averages apredetermined number of recognition scores calculated by the repetitionof Steps S7 and S8 for each of a plurality of parts to calculate theindex values of the plurality of parts of the subject.

Then, in Step S11, the part narrowing-down unit 11 narrows down, as adetermination target part of the imaging part, the parts having indexvalues, which are calculated in Step S10, greater than thenarrowing-down threshold value from among the plurality of parts of thesubject. For example, in a case in which the plurality of parts of thesubject include the heart and the lung, the index value of the heart isgreater than the narrowing-down threshold value, and the index value ofthe lung is equal to or lower than the narrowing-down threshold value,the heart remains as the determination target part and the lung isexcluded from the determination target part. Hereinafter, for thepurpose of description, the determination target parts which arenarrowed down in Step S11 from among the plurality of parts of thesubject are referred to as target parts.

Then, in Step S12, in a case in which the image acquisition unit 3acquires a new ultrasound image, the process proceeds to Step S13.

In Step S13, the image recognition unit 9 calculates the recognitionscore of the part that is ranked first according to the decideddetermination order among the determination target parts narrowed downin Step S11, for the latest ultrasound image acquired in Step S12. Forexample, in a case in which the plurality of parts of the subjectinclude the heart, the lung, and the right abdominal area, and areranked in advance such that the heart is ranked first, the lung isranked second, and the right abdominal area is ranked third, and theheart and the right abdominal area are narrowed down as thedetermination target part in Step S11, the heart is ranked first and theright abdominal area is ranked second. Therefore, in this case, therecognition score of the heart is calculated.

Then, in Step S14, the part determination unit 12 performs thresholdvalue determination of whether the recognition score of one partcalculated in Step S13 is greater than a determination threshold value.The determination threshold value is the threshold value of therecognition score in part determination, and the same determinationthreshold value can be used for all of the parts. In a case in which itis determined in Step S14 that the recognition score of one part isequal to or less than the determination threshold value, it isdetermined that it is difficult to decide the imaging part as the partwhose recognition score has been calculated in Step S13, and the processproceeds to Step S15.

In Step S15, the apparatus control unit 14 determines whether thethreshold value determination for the recognition scores of all of theparts among the target parts narrowed down in Step S11 has beenperformed in Step S14. Further, in a case in which it is determined inStep S15 that the threshold value determination for the recognitionscores of all of the narrowed-down target parts has not been performedin Step S14, the process proceeds to Step S16.

In Step S16, the apparatus control unit 14 updates a determination part.That is, the apparatus control unit 14 changes the part, of which therecognition score is to be calculated in the next Step S13, from thepart that is ranked first to the part that is ranked second in thedecided determination order, among the parts narrowed down in Step S11.Hereinafter, for the purpose of description, the ranked part for whichthe determination in Step S14 is to be performed, among the plurality ofparts of the subject is referred to as the determination part. In a casein which the determination part is updated, the process returns to StepS13 in order to determine the imaging part for the next part on thebasis of the determination order.

In Step S13 performed for the second time, only the recognition score ofthe part that is ranked second in the decided determination orderdecided among the parts narrowed down in Step S11 is calculated for theultrasound image acquired in Step S12. Then, in Step S14, the partdetermination unit 12 determines whether the recognition score of thepart that is ranked second in the determination order is greater thanthe determination threshold value. Here, in a case in which it isdetermined that the recognition score is equal to or less than thedetermination threshold value, the process proceeds to Step S15.

As such, as long as it is determined in Step S14 that the recognitionscore of the determination part is equal to or less than thedetermination threshold value, Steps S13 to S16 are repeated for thetarget parts narrowed down in Step S11, according to the determinationorder decided in Step S11. In a case in which it is determined in StepS15 that the threshold value determination for the recognition scores ofall of the target parts narrowed down in Step S11 has been performed inStep S14 as a result of the repetition of Steps S13 to S16, it isdetermined that it is difficult to decide the part included in theultrasound image acquired in Step S12 to be any of the plurality ofparts of the subject, and the process returns to Step S8. In thesubsequent Steps S8 to S14, the index values of the plurality of partsof the subject are newly calculated on the basis of the newly calculatedrecognition scores of the plurality of parts of the subject, and thedetermination target parts of the imaging part are newly narrowed downon the basis of the index values. In addition, the recognition scoresare calculated for the ultrasound image newly acquired in Step S12according to the decided determination order of the narrowed-down parts,and part determination is performed for the imaging part on the basis ofthe recognition scores.

In a case in which it is determined in Step S14 that the recognitionscore of the determination part is greater than the determinationthreshold value, the process proceeds to Step S17.

In Step S17, the part determination unit 12 decides the imaging partwhose image is currently captured, as the determination part having therecognition score that is determined to be greater than thedetermination threshold value in Step S14. Then, the part determinationoperation ends.

In the ultrasound diagnostic apparatus 1 according to Embodiment 1described above, in a case in which part determination is performed, theparts with a high probability of being the imaging part whose image iscurrently captured are narrowed down as the part, which is the target ofthe part determination, for the imaging part, and a plurality of partsof the subject are sequentially determined according to the decideddetermination order for the narrowed-down parts. Therefore, it ispossible to reduce the calculation load of the ultrasound diagnosticapparatus 1 and to reduce the time required to determine the imagingpart.

The index value calculation unit 10 averages the recognition scores ofthe plurality of parts of the subject calculated for a plurality ofultrasound images to calculate the index values of the plurality ofparts of the subject. However, for example, the number of ultrasoundimages required for the index value calculation unit 10 to calculate theindex value may be set by the operator through the operation unit 15 orthe like, or may be stored in the index value calculation unit 10 andthe storage unit 16 in advance.

In addition, the index value calculation unit 10 may calculate the indexvalue using various methods other than the method of averaging therecognition scores of each of the plurality of parts of the subject. Forexample, the index value calculation unit 10 may use the medians of therecognition scores of the plurality of parts of the subject calculatedfor a plurality of ultrasound images as the index values of theplurality of parts of the subject.

In addition, for example, the index value calculation unit 10 may usethe maximum values of the recognition scores of the plurality of partsof the subject calculated for a plurality of ultrasound images, as theindex values of the plurality of parts of the subject. Further, theindex value calculation unit 10 may use the minimum values of therecognition scores of the plurality of parts of the subject calculatedfor a plurality of ultrasound images, as the index values of theplurality of parts of the subject.

Furthermore, for example, the index value calculation unit 10 may useweighted mean values obtained by weighting and averaging the recognitionscores of the plurality of parts of the subject calculated for aplurality of ultrasound images, as the index values of the plurality ofparts of the subject. In this case, the index value calculation unit 10may calculate the weighted mean value by giving a larger weight to therecognition score calculated for an ultrasound image more recentlyacquired by the image acquisition unit 3 among the plurality ofultrasound images.

For example, the index value calculation unit 10 may give ranking scoresto a plurality of parts of the subject for each of a plurality ofultrasound images such that the ranking score becomes higher as therecognition score becomes higher. In this case, the index valuecalculation unit 10 can use the sums of the ranking scores of theplurality of parts of the subject for the plurality of ultrasoundimages, as the index values of the plurality of parts of the subject.That is, for example, for each ultrasound image, the ranking scores aregiven to the plurality of parts of the subject such that a higher scoreis given to the part with a higher recognition score in the order offive points, four points, three points, two points, and one point, andthe ranking scores of each part for the plurality of ultrasound imagesare added up to calculate the index values of the plurality of parts ofthe subject.

In addition, for example, the index value calculation unit 10 may have athreshold value of the recognition score, and calculate the index valuefrom the result of threshold value determination for the recognitionscore. In this case, the index value calculation unit 10 can use thenumber of recognition scores that are greater than the threshold valueamong the recognition scores of the plurality of parts of the subjectcalculated for the plurality of ultrasound images, as the index valuesof the plurality of parts of the subject. That is, for example, in acase in which the number of recognition scores that are greater than thethreshold value among the recognition scores of the heart calculated forthe plurality of ultrasound images is 3, the index value calculationunit 10 can set the index value of the heart to 3.

As described above, the index value calculation unit 10 can calculatethe index values on the basis of the recognition scores calculated for aplurality of frames of ultrasound images. However, the index valuecalculation unit 10 may use the recognition scores calculated for oneframe of ultrasound image as the index values. For example, the indexvalue calculation unit 10 can use the recognition scores of theplurality of parts of the subject calculated only for the latestultrasound image acquired by the image acquisition unit 3, as the indexvalues of the plurality of parts of the subject.

In the above description, in a case in which no image is included in theacquired ultrasound image, the probe state detection unit 13 determinesthat the ultrasound probe 2 is in the aerial emission state. However,the probe state detection unit 13 may compare a plurality of ultrasoundimages acquired in time series to determine whether the ultrasound probe2 is in the aerial emission state. That is, the probe state detectionunit 13 may compare a plurality of ultrasound images acquired in timeseries and may determine that, in a case in which there is no change inthe images included in the plurality of ultrasound images between theplurality of ultrasound image, the ultrasound probe 2 is not in contactwith the body surface, thereby determining that the ultrasound probe 2is in the aerial emission state. In addition, in a case in which thereis a change in the images included in the plurality of ultrasound imagesacquired in time series between the plurality of ultrasound images, theprobe state detection unit 13 may determine that a part of the subjectis included in the plurality of ultrasound images, thereby determiningthat the ultrasound probe 2 is in contact with the body surface of thesubject.

With this configuration, even in the case in which ultrasonography gelis attached to the ultrasound probe 2, the probe state detection unit 13can compare a plurality of ultrasound images acquired in time series todetermine whether the ultrasound probe 2 is in the aerial emissionstate.

In the flowchart illustrated in FIG. 4, in a case in which the probestate detection unit 13 detects a change in the imaging part, the partdetermination in Step S3 starts. This means that, in a case in which theprobe state detection unit 13 detects a change in the imaging part, theindex value calculation unit 10 starts to calculate the index value onthe basis of the recognition score calculated for a newly acquiredultrasound image. As such, it is possible to reduce the calculation loadof the ultrasound diagnostic apparatus 1 by calculating the index valuefor the ultrasound image only while the ultrasound probe 2 is in contactwith the body surface of the subject. In addition, in a case in whichthe index value calculation unit 10 calculates the index values, it ispossible to prevent the index value calculation unit 10 from using therecognition scores of the previous imaging part.

In addition, the index value calculation unit 10 may start to calculatethe index values for the plurality of parts of the subject after apredetermined period of time has elapsed since the probe state detectionunit 13 has detected a change in the imaging part. For example, the timeuntil the index value calculation unit 10 calculates the index values ofthe plurality of parts of the subject after the probe state detectionunit 13 detects a change in the imaging part may be input by theoperator through the operation unit 15 or the like, or may be stored inadvance in the storage unit 16.

The time until the ultrasound probe 2 is brought into contact with thebody surface of the subject to obtain the ultrasound image of a targetimaging part varies depending on, for example, the skill of theoperator. In some cases, immediately after the imaging part is changed,an ultrasound image that is sufficiently clear to calculate therecognition score is not obtained. For this reason, in a case in whichthe calculation of the index values of a plurality of parts of thesubject starts after a predetermined period of time has elapsed sincethe probe state detection unit 13 has detected a change in the imagingpart, it is possible to calculate the index values on the basis of aplurality of recognition scores calculated for the ultrasound image thatis sufficiently clear. Therefore, it is possible to improve the accuracyof calculating the index value.

In addition, in the flowchart illustrated in FIG. 5, Steps S12 and S13may be omitted. In that case, in a case in which the target parts whichare the targets for the determination of the imaging part are narroweddown in Step S11, the process proceeds to Step S14. In Step S14, thepart determination unit 12 compares the recognition score of the partthat is ranked first in the decided determination order among therecognition scores of the plurality of parts of the subject calculatedin Step S8 for the latest ultrasound image acquired in Step S7 with thedetermination threshold value. At that time, in a case in which therecognition score is equal to or less than the determination thresholdvalue, the process proceeds to Step S15. Further, in a case in which itis determined in Step S15 that the threshold value determination for therecognition scores of all of the target parts narrowed down in Step S11has not been performed, the process proceeds to Step S16. In a case inwhich the determination part is updated in Step S16, it is determined inStep S14 whether the recognition score of the part that is ranked secondin the determination order is greater than the determination thresholdvalue.

In the above-described embodiment, the same determination thresholdvalue is used for all of the parts by the part determination unit 12 inStep S14. However, the determination threshold value may be set for eachof the plurality of parts of the subject.

The above-mentioned ultrasound diagnostic apparatus 1 may be a portableultrasound diagnostic apparatus that is small and can be easily carriedand used or a stationary ultrasound diagnostic apparatus that isinstalled and used in, for example, a medical examination room.

In addition, the ultrasound probe 2 is not particularly limited as longas it can transmit and receive ultrasound beams to and from the subjectand may be a sector type, a convex type, a linear type, or a radialtype.

Embodiment 2

In the operation of the ultrasound diagnostic apparatus 1 illustrated inthe flowchart of FIG. 4, in a case in which the ultrasound probe 2 is inthe aerial emission state in Step S6, the process returns to Step S1.Then, in Step S3, the part determination is performed for all of theplurality of parts of the subject. However, the part of the subjectwhich has been decided in Step S3 may be excluded. In this case, it ispossible to further reduce the calculation load of the ultrasounddiagnostic apparatus 1 in the part determination.

FIG. 6 illustrates the operation of an ultrasound diagnostic apparatusaccording to Embodiment 2. Since Steps S1 to S6 in a flowchartillustrated in FIG. 6 are the same as Steps S1 to S6 in the flowchartillustrated in FIG. 4, the detailed description thereof will not berepeated.

In a case in which the probe state detection unit 13 determines that theultrasound probe 2 is in the aerial emission state in Step S6, theprocess proceeds to Step S18. In Step S18, the apparatus control unit 14determines whether all of a plurality of parts of the subject have beendecided. In a case in which it is determined in Step S18 that all of theplurality of parts of the subject have not been decided, the processproceeds to Step S19.

In Step S19, the part narrowing-down unit 11 excludes the part that hasbeen decided in the part determination of Step S3, that is, the decidedpart from the determination target in Step S3 to be performed for thenext time. In a case in which the process in Step S19 is completed, theprocess returns to Step S1. Then, in a case in which it is determined inStep S2 that the ultrasound probe 2 is not in the aerial emission state,the part determination is performed in Step S3. At that time, since theparts other than the part which has been excluded in Step S19 among theplurality of parts of the subject are the determination targets, thenumber of part candidates to be determined for the imaging part can befurther reduced as compared with that in the part determination of StepS3 performed for the first time.

Steps S1 to S19 are repeated in this way to reduce the number ofdetermination targets. As a result, in a case in which it is determinedin Step S18 that all of the plurality of parts of the subject have beendecided, the operation of the ultrasound diagnostic apparatus ends.

As such, Steps S1 to S19 are repeated to reduce the number ofdetermination targets. Therefore, it is possible to further reduce thecalculation load of the ultrasound diagnostic apparatus in the partdetermination of Step S3 whenever Step S19 is performed and to reducethe time required to determine the imaging part.

Embodiment 3

In a part determination operation in the flowchart of FIG. 5, thethreshold value determination of Step S14 is performed for only theparts which are the determination targets narrowed down in Step S11among the plurality of parts of the subject, but the threshold valuedetermination can be performed for the parts which are not narrowed downin Step S11.

FIG. 7 is a flowchart illustrating a part determination operation of anultrasound diagnostic apparatus according to Embodiment 3. Since theflowchart of FIG. 7 is the same as the flowchart of FIG. 5 except thatStep S20 is added to the flowchart of FIG. 5, the detailed descriptionof Steps S7 to S17 is omitted.

In the flowchart of FIG. 7, in a case in which the recognition scores ofthe plurality of parts of the subject are calculated for a predeterminednumber of frames of ultrasound images in Steps S7 to S9, the indexvalues of the plurality of parts of the subject are calculated in StepS10. In a case in which the target parts which are the determinationtargets for the imaging part are narrowed down on the basis of theseindex values in Step S11, a new ultrasound image is acquired in StepS12. In Steps S13 to S16 following Step S12, the threshold valuedetermination is sequentially performed for the target parts of thesubject narrowed down in Step S11. As a result, in a case in which it isdetermined in Step S15 that the threshold value determination for therecognition scores of all of the target parts narrowed down in Step S11has been performed, the process proceeds to Step S20.

In Step S20, it is determined whether there is a part having arecognition score greater than the determination threshold value for theparts which are not narrowed down in Step S11, that is, the partsexcluding the target parts that are narrowed down in Step S11 among theplurality of parts of the subject. The process performed in Step S20will be described in detail below with reference to FIG. 8. In a case inwhich it is determined in Step S20 that there is no part having arecognition score greater than the determination threshold value amongall of the parts which are not narrowed down in Step S11, it isdetermined that it is difficult to decide the part included in theultrasound image acquired in Step S12 to be any of the plurality ofparts of the subject, and the process returns to Step S8.

Meanwhile, in a case in which it is determined in Step S20 that there isa part having a recognition score greater than the determinationthreshold value among all of the parts which are not narrowed down inStep S11, the process proceeds to Step S17, the imaging part whose imageis currently captured is decided to be a part having a recognition scoregreater than the determination threshold value, and the partdetermination operation ends.

Here, Step S20 of the flowchart in FIG. 7 will be described using FIG.8. In FIG. 8, for the purpose of description, Steps S7 to S14 and StepsS16 and S17 are omitted.

In a case in which the process in Step S20 starts, first, a process inStep S21 is performed. In Step S21, the image recognition unit 9calculates the recognition score of one part which is not narrowed downin Step S11 for the ultrasound image acquired in Step S12. In that case,the part of the subject of which the recognition score is calculated isa part ranked first in the decided order among the parts which are notnarrowed down in Step S11. For example, in a case in which the pluralityof parts of the subject include the heart, the lung, and the rightabdominal area, the heart, the lung, and the right abdominal area areranked in the decided order, and among these parts, only the lung isnarrowed down as the target part in Step S11, the recognition score ofthe heart that is ranked first in the decided order among the heart andthe right abdominal area which are not narrowed down in Step S11 iscalculated in Step S21.

Then, in Step S22, the part determination unit 12 determines whether therecognition score calculated in Step S21 is greater than thedetermination threshold value. In a case in which it is determined thatthe recognition score calculated in Step S21 is equal to or less thanthe determination threshold value, the process proceeds to Step S23.

In Step S23, the apparatus control unit 14 determines whether thethreshold value determination for the recognition scores of all of theparts which are not narrowed down in Step S11 has been performed in StepS22. In a case in which it is determined in Step S23 that the thresholdvalue determination for the recognition scores of all of the parts whichare not narrowed down in Step S11 has not been performed in Step S22,the process proceeds to Step S24 in order to perform the threshold valuedetermination for the recognition score of the next part in the decideddetermination order.

In Step S24, the apparatus control unit 14 determines, as thedetermination part, the next part according to the decided order amongthe parts which are not narrowed down in Step S11. For example, in acase in which the plurality of parts of the subject include the heart,the lung, and the right abdominal area, the heart, the lung, and theright abdominal area are ranked in the decided order, and among theseparts, only the lung is narrowed down as the target part in Step S11,the right abdominal area as the part that is ranked second in thedecided order among the heart and the right abdominal area which are notnarrowed down in Step S11 is determined as the determination part.

In a case in which the determination order is updated in Step S24, theprocess returns to Step S21. As such, as long as the recognition scoreof each of the parts which are not narrowed down in Step S11 is equal toor less than the determination threshold value, Steps S21 to S24 arerepeated. As a result, in a case in which it is determined in Step S23that the threshold value determination of all of the parts which arenarrowed down in Step S11 has been performed in Step S22, the processreturns to Step S8. This is the same as a case in which it is determinedin Step S20 that there is no part having a recognition score greaterthan the determination threshold value among all of the parts which arenot narrowed down in Step S11.

In a case in which it is determined in Step S22 that the recognitionscore of the part as the determination part among the parts narroweddown in Step S11 is greater than the determination threshold value, theprocess proceeds to Step S17. This is the same as a case in which it isdetermined in Step S20 that there is a part having a recognition scoregreater than the determination threshold value among all of the partswhich are not narrowed down in Step S11.

As described above, with the part determination operation of Embodiment3 illustrated in FIGS. 7 and 8, it is possible to perform the thresholdvalue determination for the recognition scores of the parts of thesubject which are not narrowed down in Step S11. Therefore, even in acase in which the part corresponding to the imaging part among theplurality of parts of the subject is excluded from the target part dueto the accuracy of the index values calculated in Step S10, the partdetermination unit 12 can perform the threshold value determination foreach part without exception, and it is possible to improve the accuracyof the part determination.

Embodiment 4

In the part determination operation according to Embodiments 1 and 3illustrated in FIGS. 5 and 7, in the threshold value determination ofStep S14, the recognition score of one part of the subject which hasbeen calculated for the ultrasound image newly acquired in Step S12 bythe image recognition unit 9 is used. However, recognition scores forpart determination which have been calculated on the basis of therecognition scores calculated for a plurality of ultrasound images maybe used for the threshold value determination.

FIG. 9 is a flowchart illustrating a part determination operation of anultrasound diagnostic apparatus according to Embodiment 4. The flowchartillustrated in FIG. 9 is the same as the flowchart according toEmbodiment 1 illustrated in FIG. 5 except for Steps S20 to S22.

In the flowchart illustrated in FIG. 9, in a case in which the partdetermination operation starts, first, Steps S7 to S9 are repeated untilthe recognition scores of a plurality of parts of the subject arecalculated for a predetermined number of frames of ultrasound images.Here, the predetermined number of frames is referred to as a firstpredetermined number of frames for the purpose of description. In a casein which it is determined in Step S9 that the recognition scores of theplurality of parts of the subject are calculated for the firstpredetermined number of frames of ultrasound images, the processproceeds to Step S10. In a case in which the index values of theplurality of parts of the subject are calculated from the recognitionscores of the plurality of parts of the subject calculated for the firstpredetermined number of frames of ultrasound images in Step S10, targetparts which are the targets for the part determination are narrowed downfrom among the plurality of parts of the subject in Step S11.

Then, an ultrasound image is newly acquired in Step S12 and the processproceeds to Step S20. Step S20 is the same as Step S8 in the flowchartillustrated in FIG. 5. In a case in which the recognition scores of theplurality of parts of the subject are calculated for the latestultrasound image in Step S25, the process proceeds to Step S26.

In Step S26, the apparatus control unit 14 determines whetherrecognition scores have been calculated for a second predeterminednumber of frames of ultrasound images acquired in Step S12. This is toobtain the number of recognition scores necessary to calculate therecognition scores for part determination. Therefore, in a case in whichit is determined in Step S26 that the recognition scores have not beencalculated for the second predetermined number of frames of ultrasoundimages, the process returns to Step S12, and an ultrasound image isnewly acquired. Then, in Step S25, the recognition scores of theplurality of parts of the subject are newly calculated.

Here, the first predetermined number of frames in Step S9 and the secondpredetermined number of frames in Step S26 may be equal to or differentfrom each other. For the purpose of description, it is assumed that thefirst predetermined number of frames and the second predetermined numberof frames are different from each other.

In a case in which it is determined in Step S26 that the recognitionscores have been calculated for the second predetermined number offrames of ultrasound images, the process proceeds to Step S27. In StepS27, the image recognition unit 9 averages the recognition scores of thedetermination part which have been calculated in Step S25 for the secondpredetermined number of frames of ultrasound images. In that case, thepart of which the recognition score is calculated is a determinationpart ranked first in the decided determination order among the targetparts narrowed down in Step S11. As such, the image recognition unit 9calculates the mean value of the recognition scores of the determinationpart as the recognition score for determining the imaging part. In thiscase, it is preferable that a plurality of ultrasound images used torecognize the determination part are continuous in time series.

Then, in Step S14, the apparatus control unit 14 determines whether therecognition score for determination calculated in Step S27 is greaterthan the determination threshold value. In a case in which it isdetermined in Step S14 that the recognition score for determination isequal to or less than the determination threshold value, it is difficultto decide the determination part with respect to the imaging part, andthe process proceeds to Step S15. In a case in which it is determined inStep S15 that the threshold value determination for the recognitionscores of all of the target parts narrowed down in Step S11 has not beenperformed, the determination part is updated in Step S16, and theprocess returns to Step S27.

In a case in which the process returns to Step S27, the recognitionscore for determination is calculated for the part that is ranked secondin the decided determination order among the target parts narrowed downin Step S11. As such, as long as the recognition score for determinationis equal to or less than the determination threshold value in Step S14,Steps S27 to S16 are repeated. In a case in which it is determined inStep S14 that the recognition score for determination is greater thanthe determination threshold value, the process proceeds to Step S17, andthe imaging part is decided. Then, the part determination operationillustrated in the flowchart of FIG. 9 ends.

As such, since the recognition score for part determination iscalculated from the recognition scores calculated for a plurality ofultrasound images, it is possible to improve the accuracy of determiningthe imaging part. For example, even in a case in which a part of thesubject included in some of the ultrasound images acquired in Step S12is not sufficiently clear as the image recognition target, the accuracyof deciding the imaging part is improved.

In the above description, in a case in which the recognition score fordetermining the imaging part is calculated in Step S27, the recognitionscores for the second predetermined number of frames of ultrasoundimages acquired in Step S12 are used. However, the recognition score fordetermining the imaging part may be calculated in Step S27 on the basisof both the recognition scores calculated in Step S25 and therecognition scores for the first predetermined number of frames ofultrasound images. That is, the second predetermined number of framesmay be the sum of the first predetermined number of frames and thenumber of frames of ultrasound images acquired in Step S12.

At that time, in a case in which the second predetermined number offrames is equal to or less than the first predetermined number offrames, that is, in a case in which the number of recognition scores ofa plurality of parts of the subject required to calculate therecognition score for determining the imaging part in Step S27 is equalto or less than the number of recognition scores required to calculatethe index values in Step S10, Step S12, Step S25, and Step S26 can beomitted. Therefore, it is possible to further reduce the time requiredto determine the imaging part.

Embodiment 5

In the part determination operations according to Embodiments 1, 3, and4 illustrated in FIGS. 5, 7, and 9, the determination target parts forthe imaging part are narrowed down from among a plurality of parts ofthe subject on the basis of the index values of the plurality of partsof the subject. However, at that time, the determination order in whichthe threshold value determination is performed can be decided.

FIG. 10 illustrates the configuration of an ultrasound diagnosticapparatus 21 according to Embodiment 5. The ultrasound diagnosticapparatus 21 according to Embodiment 5 is the same as the ultrasounddiagnostic apparatus 1 according to Embodiment 1 illustrated in FIG. 1except that the ultrasound diagnostic apparatus 21 includes an orderdecision unit 22. Therefore, components other than the order decisionunit 22 are denoted by the same reference numerals and the detaileddescription thereof will not be repeated.

In the ultrasound diagnostic apparatus 21 according to Embodiment 5, theorder decision unit 22 is connected to the part narrowing-down unit 11,and the order decision unit 22 is connected to the part determinationunit 12. In addition, the order decision unit 22 is connected to theapparatus control unit 14.

The order decision unit 22 decides a determination order in which partdetermination is performed for the plurality of parts of the subject, onthe basis of the index values of the plurality of parts of the subjectcalculated by the index value calculation unit 10. In that case, theorder decision unit 22 decides the determination order such that thepart with a larger index value is ranked higher.

FIG. 11 is a flowchart illustrating a part determination operation ofthe ultrasound diagnostic apparatus 21 according to Embodiment 5. Theflowchart illustrated in FIG. 11 is the same as the flowchartillustrated in FIG. 5 except that Step S11 in the flowchart according toEmbodiment 1 illustrated in FIG. 5 is replaced with Step S28. Therefore,the detailed description of the same steps as those in the flowchart ofFIG. 5 will not be repeated.

In a case in which the part determination operation of the ultrasounddiagnostic apparatus 21 according to Embodiment 5 starts, therecognition scores of a plurality of parts of the subject are calculatedfor a predetermined number of frames of ultrasound images in Steps S7 toS9. Then, in Step S10, index values are calculated on the basis of therecognition scores.

Then, in Step S28, first, the part narrowing-down unit 11 narrows downthe target parts to be determined with respect to the imaging part whoseimage is currently captured, on the basis of the index values of theplurality of parts of the subject calculated in Step S10. Then, theorder decision unit 22 decides the determination order of a plurality ofparts narrowed down by the part narrowing-down unit 11 such that thepart with a larger index value is ranked higher.

Then, in Steps S12 and S13, an ultrasound image is newly acquired, andonly the recognition score of a part that is ranked first in thedetermination order among the target parts narrowed down in Step S28 iscalculated. Then, in Steps S14 to S16, it is determined whether therecognition score is greater than the determination threshold value andthe determination part is updated. In Step S16, the determination partis continuously updated. As a result, in a case in which it isdetermined in Step S15 that the threshold value determination for therecognition scores of all of the target parts narrowed down in Step S28has been performed in Step S14, it is determined that it is difficult todecide the part included in the ultrasound image acquired in Step S12 tobe any of the plurality of parts of the subject, and the process returnsto Step S8. Then, the part determination operation starts again.

In a case in which it is determined in Step S14 that the recognitionscore of the part calculated in Step S13 is greater than the thresholdvalue, the process proceeds to Step S17. In a case in which the part tobe determined with respect to the imaging part whose image is currentlycaptured is decided in Step S17, the part determination operation ends.

As described above, in the part determination operation according toEmbodiment 5, since the target parts for the determination of theimaging part whose image is currently captured are narrowed down and thedetermination order of the narrowed-down target parts is decided, it ispossible to perform the threshold value determination of the recognitionscore sequentially from the part with a high probability of being theimaging part. Therefore, it is possible to reduce the calculation loadof the ultrasound diagnostic apparatus 21 in the part determination andto reduce the time required to determine the imaging part.

In Embodiment 5, the order decision unit 22 decides the determinationorder of the target parts of the subject which are narrowed down by thepart narrowing-down unit 11. However, similarly to Embodiment 3, in acase in which the threshold value determination is performed for theparts which are not narrowed down by the part narrowing-down unit 11,the determination order of the parts which are not narrowed down by thepart narrowing-down unit 11 can be decided. In this case, similarly to acase in which the determination order of the target parts is decided,the order decision unit 22 can decide the order of the parts which arenot narrowed down by the part narrowing-down unit 11, on the basis ofthe index values of the parts. Although not illustrated, for example,the order decision unit 22 may decide the order of the parts which arenot narrowed down by the part narrowing-down unit 11, immediately beforethe step corresponding to Step S20 in the flowchart of Embodiment 3illustrated in FIG. 7.

In addition, in some cases, the index value calculation unit 10 maycalculate the same index values among the index values of the pluralityof parts of the subject. The order decision unit 22 decides thedetermination order such that the part with a larger index value isranked higher. Therefore, in a case in which the same index values amongthe index values of the plurality of parts which are narrowed down bythe part narrowing-down unit 11 are calculated, it is difficult for theorder decision unit 22 to decide the determination order. In that case,the index value calculation unit 10 can calculate the index valuesagain. Further, in that case, the index value calculation unit 10 cancalculate the index values again, using the recognition scorescalculated for an ultrasound image group that includes the latestultrasound image acquired by the image acquisition unit 3 and consistsof ultrasound images whose number is less than the number of theplurality of ultrasound images used in a case in which the same indexvalues have been calculated. It is preferable that the ultrasound imagegroup used here is continuously acquired in time series by the imageacquisition unit 3.

In addition, in a case in which the index values are calculated again,the index value calculation unit 10 may calculate the index values,using the recognition scores calculated for an ultrasound image groupconsisting of a plurality of ultrasound images that are acquired by theimage acquisition unit 3 before the latest ultrasound image in timeseries and are continuous in time series.

The ultrasound diagnostic apparatuses according to the embodiments ofthe invention have been described in detail above. However, theinvention is not limited to the above-mentioned examples and variousmodifications and changes may be made without departing from the scopeand spirit of the invention. In addition, a plurality of embodimentsdescribed above may be appropriately combined with each other.

EXPLANATION OF REFERENCES

1, 21: ultrasound diagnostic apparatus

2: ultrasound probe

2A: transducer array

3: image acquisition unit

4: receiving unit

5: transmitting unit

6: image generation unit

7: display control unit

8: display unit

9: image recognition unit

10: index value calculation unit

11: part narrowing-down unit

12: part determination unit

13: probe state detection unit

14: apparatus control unit

15: operation unit

16: storage unit

17: amplification unit

18: A/D conversion unit

19: B-mode processing unit

20: image processing unit

22: order decision unit

What is claimed is:
 1. An ultrasound diagnostic apparatus comprising: anultrasound probe; a transmission circuit configured to transmit anultrasound beam from the ultrasound probe to a subject; a receptioncircuit configured to receive ultrasound echoes from the subject by theultrasound probe to generate element data; and a processor configured togenerate an ultrasound image on the basis of the element data generatedby the reception circuit, perform image recognition for the ultrasoundimage thus generated to calculate recognition scores of a plurality ofparts of the subject, calculate index values of the plurality of partson the basis of the recognition scores of the plurality of partscalculated for a predetermined number of ultrasound images, narrow downtarget parts for which part determination is to be performed, from theplurality of parts on the basis of the index values, and determine animaging part of the subject on the basis of the recognition scores forthe target parts narrowed down.
 2. The ultrasound diagnostic apparatusaccording to claim 1, wherein the processor uses, as the index values ofthe plurality of parts, recognition scores of the plurality of partscalculated for a latest ultrasound image acquired.
 3. The ultrasounddiagnostic apparatus according to claim 1, wherein the processorcalculates the index values of the plurality of parts using recognitionscores of the plurality of parts calculated for each of a plurality ofultrasound images which are continuously acquired in time series andinclude a latest ultrasound image acquired.
 4. The ultrasound diagnosticapparatus according to claim 3, wherein the processor uses mean valuesor medians of the recognition scores of the plurality of partscalculated for the plurality of ultrasound images, as the index valuesof the plurality of parts.
 5. The ultrasound diagnostic apparatusaccording to claim 3, wherein the processor uses maximum values orminimum values of the recognition scores of the plurality of partscalculated for the plurality of ultrasound images, as the index valuesof the plurality of parts.
 6. The ultrasound diagnostic apparatusaccording to claim 3, wherein the processor calculates weighted meanvalues of the recognition scores of the plurality of parts by giving alarger weight to an ultrasound image more recently acquired among theplurality of ultrasound images, and uses the weighted mean values as theindex values of the plurality of parts.
 7. The ultrasound diagnosticapparatus according to claim 3, wherein the processor gives rankingscores to the plurality of parts for each of the plurality of ultrasoundimages such that the part with a higher recognition score has a higherranking score, and uses sums of the ranking scores of the plurality ofparts for the plurality of ultrasound images as the index values of theplurality of parts.
 8. The ultrasound diagnostic apparatus according toclaim 3, wherein the processor has a threshold value of the recognitionscore, and uses the number of recognition scores greater than thethreshold value among the recognition scores of the plurality of partscalculated for the plurality of ultrasound images, as the index value ofeach of the plurality of parts.
 9. The ultrasound diagnostic apparatusaccording to claim 1, wherein the processor detects a change in animaging part caused by movement of the ultrasound probe and starts tocalculate the index value after detecting the change in the imagingpart.
 10. The ultrasound diagnostic apparatus according to claim 2,wherein the processor detects a change in an imaging part caused bymovement of the ultrasound probe and starts to calculate the index valueafter detecting the change in the imaging part.
 11. The ultrasounddiagnostic apparatus according to claim 3, wherein the processor detectsa change in an imaging part caused by movement of the ultrasound probeand starts to calculate the index value after detecting the change inthe imaging part.
 12. The ultrasound diagnostic apparatus according toclaim 1, wherein the processor has a narrowing-down threshold value forthe index value, and narrows down the plurality of parts of the subjecthaving the index value greater than the narrowing-down threshold value,as the target parts.
 13. The ultrasound diagnostic apparatus accordingto claim 2, wherein the processor has a narrowing-down threshold valuefor the index value, and narrows down the plurality of parts of thesubject having the index value greater than the narrowing-down thresholdvalue, as the target parts.
 14. The ultrasound diagnostic apparatusaccording to claim 3, wherein the processor has a narrowing-downthreshold value for the index value, and narrows down the plurality ofparts of the subject having the index value greater than thenarrowing-down threshold value, as the target parts.
 15. The ultrasounddiagnostic apparatus according to claim 1, wherein the processor decidesa determination order in which part determination is performed for theplurality of parts, on the basis of the index values and decides thedetermination order such that the part with a larger index value isranked higher.
 16. The ultrasound diagnostic apparatus according toclaim 2, wherein the processor decides a determination order in whichpart determination is performed for the plurality of parts, on the basisof the index values and decides the determination order such that thepart with a larger index value is ranked higher.
 17. The ultrasounddiagnostic apparatus according to claim 3, wherein the processor decidesa determination order in which part determination is performed for theplurality of parts, on the basis of the index values and decides thedetermination order such that the part with a larger index value isranked higher.
 18. The ultrasound diagnostic apparatus according toclaim 1, wherein in a case in which the imaging part is not decided forall of the target parts narrowed down, the processor determines theimaging part for the parts other than the target parts among theplurality of parts.
 19. A method for controlling an ultrasounddiagnostic apparatus, the method comprising: transmitting an ultrasoundbeam from an ultrasound probe to a subject to generate an ultrasoundimage; performing image recognition for the ultrasound image tocalculate recognition scores of a plurality of parts of the subject;calculating index values of the plurality of parts on the basis of therecognition scores of the plurality of parts calculated for apredetermined number of ultrasound images; narrowing down target partsfor which part determination is to be performed, from the plurality ofparts on the basis of the index values; and determining an imaging partof the subject on the basis of the calculated recognition scores for thenarrowed-down target parts.
 20. A readable recording medium recording aprogram for controlling an ultrasound diagnostic apparatus, the programcausing a processor to perform: a step of transmitting an ultrasoundbeam from an ultrasound probe to a subject to generate an ultrasoundimage; a step of performing image recognition for the ultrasound imageto calculate recognition scores of a plurality of parts of the subject;a step of calculating index values of the plurality of parts on thebasis of the recognition scores of the plurality of parts calculated fora predetermined number of ultrasound images; a step of narrowing downtarget parts for which part determination is to be performed, from theplurality of parts on the basis of the index values; and a step ofdetermining an imaging part of the subject on the basis of thecalculated recognition scores for the narrowed-down target parts.